def file_write():
    with open('aa.txt', 'w', encoding='utf-8') as file:
        file.write('开始写入..')

def file_read():
    with open('aa.txt', 'r', encoding='utf-8') as file:
        print(file.read())

def file_copy(src_file, tar_file):
    with open(src_file, 'r', encoding='utf-8') as file:
        with open(tar_file, 'w', encoding='utf-8') as file1:
            file1.write(file.read())

if __name__ == '__main__':
    file_write()
    file_read()
    file_copy('./aa.txt', 'bb.txt')
